In order to understand this first form of resurrection one must understand that there exists a process called materialisation. In this process a discarnated being, a so-called "spirit", forms a temporary physical body with which, in the most fortunate cases, it can for a moment appear as a physical being. It can thus talk, hear and see on the physical plane and cannot actually be distinguished from an ordinary physical being. This process is, as previously mentioned, not connected with any particular moral standard. It is a characteristic that everyone more or less possesses, even if, among ordinary people, it is quite latent and very seldom manifested or used outside ordinary materialisation, that is, the creation of an embryo in the mother's womb. But here it does not happen as an awake, day-conscious concentration or act of will. Here it is an automatic function borne by the mental energies belonging to the first cosmic basic energy, "instinct", in the same way as the other independently working organs in the organism or the body. The same energy and automatic function promotes the creation of plants' organisms. While this latter form of materialisation is an automatic, recurrent event in every individual's reincarnation or rebirth, the other form of materialisation is, as previously mentioned, only an act of will maintained by awake, day-conscious concentration of thought.
      Even if this temporary act of materialisation is not dependent on any exceptional moral standard it is to the very highest degree dependent on a very highly developed ability to concentrate, an ability that can be developed by special training. And even with this ability, further special conditions are essential for the act to take place. A discarnated spirit cannot therefore as a matter of course materialise itself whenever and wherever it likes. It can materialise itself on the physical plane only where that material on which a materialisation is based is to be found. This matter, as a kind of finer physical substance which we may call "A-substance", is to be found in some terrestrial human beings only in insignificant amounts, while in others it is to be found in abundance. The above-mentioned substance has the characteristic that it can quickly or with lightening speed connect with and let itself be controlled or formed by a particular psychic or spiritual power, which we can call "A-power". Through this connection a concentration takes place in the A-substance whereby the latter becomes physically visible. It is this rendering visible we see as a materialisation. As regards the A-power, it can be traced to an automatic releasing process that, in the given moment of materialisation, is kept in motion by a discarnated being's concentration of will behind its talent kernel for creating and building up a physical organism. The success or perfection of the materialisation will therefore depend totally on the strength of the discarnated being's concentration and likewise on whether there is sufficient A-substance present. Whether there is enough of this substance is dependent on the presence of one or more people possessing copious amounts of the necessary A-substance. Such people are termed "materialisation mediums". When such a being places himself at the disposal of a discarnated spirit, and the same spirit can thereby, with his A-power, come into contact with the medium's A-substance, the materialisation begins, borne by the concentration of the discarnated spirit. The discarnated spirit's talent kernel for the building up of a physical body, which is otherwise at rest during the spirit's discarnated state, begins to function. From this, so-to-speak, psycho-physical, chemical connection between the A-substance of the medium and the A-power of the discarnated spirit there thus, with the aid of the talent kernel, arises a re-forming of a physical body for the spirit. It will of course be easiest for this physical body to be a true copy of the spirit's last physical body, from which it was separated at its physical death, even though it can, under certain fortunate circumstances, also be a perfect copy of other previous physical organisms.
      Since the A-substance is substance borrowed from the medium, and during the materialisation is still connected to the medium, it will go back to this, its source, to the same extent as the discarnated spirit's A-power is exhausted and the concentration maintaining the materialisation is relaxed. The materialised body is dissolved and the A-substance again becomes invisible and returns to its source or originator. It is this aspect of the materialisation we term dematerialisation.